Apparatus for reflecting and directing light.



No. 817,621. PATENTED APR. l0, 1906 A. BOASYL G. RODRIGUES-ELY. APPARATUS POR RBPLECTN'G AND DRECTING LIGHT APPLICATION PLED `TAN. 30, 1905.

ALFRED BOAS AND CAlVlILLE RQDRlGUES-ELY, 0F PARIS, FRiKlE.

Specification of `Letters Pate-lit.

i resented Aprn 1o, 190e.

Application filed January, 190. Serial Eo. 243,447.0.

To AZZ whom it may concer-1e:

Be it known that we, ALFRED BOAS and CAMILLE Roni-uorns-ELY, engineers, citizens of the French Republic, residing' at Paris.'

F rance, have invented certain new and useful Improvements in Apparatus Vfor Reflecting and 'Directingr Light, of Whicli the following is a specification.v

This invention relates to a reilector for ex tended luminous sources formed hy two burners, and has for its object to provide a retlector in which an amount as great as possiole of luminous rays ernitted by the sources of light issue in a parallel direction with the axis of this reflector.

rihe new reflector is constituted bya planoconvex lens, a parabolic inirror, and an elliptic mirror, which are disposed in order that the focus oi the paraboloid, the v'focus of the lens, and the lore focus of the ellipsoid coincide.

Retiectors are known having a lens, a puraholic and a spherical mirror in which the focus ot the paraholoid, the focus of the lens, and the center yof the sphere coincide. l/Vith such a rellector and with a source oi: light reduced to a, point and placed at the focus the totality ot the luminous rnys issue in a parallel direction with the axis ol" this reflector. li such c, reflector be used with two sources of light, one at-the focus and the other behind or before it, the totality of the luminous rays emitted hy the source placed at the Vlocus-- i. c., fifty per cent. ol' the total lighte-would issue in a parallel direction with the ol' the reflector. The rays emitted by the other soluce-i. .f fifty percent. ol' the total light- Would issue in a convergent or divergent di rection.

According to the invention, in these reflectors an elliptic mirror is substituted to the spherical one. The two sources olv light are placed on the two loci of the eliipsoid, ther fore one coinciding with the focus oi' the pas raboloid und of the lens. ,By this arrangelnent the amount of rays which issue in n. parallel direction with the axis ol'` the rellector is greatly increased.

ln the drawingr is shown flianietricnlly n section through the axis ol a rellcctor in accordance with this invention.

The rcilector comprises a plano-cmivcx L lens l, a mirror 2,hav1ng the shane ol' a ,on-

an ellipsoid. rEhe focus G of the lens, the focus of the peraholoid, and the fore. focus of the ellipsoid coincide. The ellipsoid and the pcraboloid intersect according to a circle having the same diameter as the lens and situated in a plane perpendicular to the axis of the apparatus and passing through the focus O of the paraholoid. The part of the ellipsoid which Would be before this plane .is suppressed, as Well as the Y art ot the paraboloid which is behind this p ane.

The sources of light are disposed at the two B B strike the paraholoid or the lens and is- A luminous ray (l E, for inst-ance, emitted by the source (l at the left of E B between B C focus O, strikes again the ellipsoid in E', is again reflected, passes through the focus 0, and finally strikes the paraboloid at i112 or the lens. a parallel direction with the axis (l A.. The rays emitted from the source (l in the rear part C D C- strike only once the ellipsoid, return through the -foeus O', and strike the paraboloid or the lens Without passingr again through their focus O. They issue from the apparatus either convergirngr or diverging T e rays emitted by the source O in the rear port C l) C-i. e., aboutwthirty per cent. of the light emitted by the-source O and fifteen per cent. of the total lightdo not issue in a parallel direction with (l A. The rays emitted ellipsoid,arc reflected once, pass through the focus (i, strike the paral'ioloid or the lens, and issue iny :i parallel direction with O A. The other rays emitted by c., about forty percent. of the light' emitted by the source (l and twenty per cent. of the total light-strike directly the paraboloid or the lens and issue citlicr divergincr or converging. Thus sixty-live per cent. of the rays issue in a parallel direction with the axis O A.

lia ving,r thus fully described our invention, y what We claim ns newfand desire to secure by l'ietters Patent, is-

fi reflector Afor extended luniinous sources 1 l'ornued by two sources of light, said reflector raboloid, and a mirror 3, having the shape'ot 'foci O O of the ellipsoid. The luminous" rays emitted by the source O at the right of sue in a parallel direction with the axis G A.'

'or B C strikes the ellipsoid, returns to the\ by the source (5) at thercar of B B strike the This ray issues from the apparatus in IOD ' comprising a mirror praboidal Vin cnour, a"

plano-convex lensmrmlrror lhpsoldal mconset our hands 1n presence of tWo subscrlblng 1g,

In testimanjr whereof We have hereunto Witnessesy ALFRED BOAS.. CAMILLE RODRIGUES-ELY.

ZVitnesses'Lr HIPPOLYTE' JOTTEL, v BAUL' BLUM.

tom and havm th two Sou'ces of gh'-O-- cated at the fom thexeof, the saidmx'iors intrsecting each other on a cirle of a diameter equal to that of .the lensrthe plime of the said Qyce passing through the front source, of Eight.' 1l f 

